Well, I set out to debunk the economics of it, but my back of the envelope calculations gave better numbers than I was expecting. You're right, though, lots of

Well, I set out to debunk the economics of it, but my back of the envelope calculations gave better numbers than I was expecting. You're right, though, lots of factors I have failed to take into account. Another big one not mentioned yet: ever noticed how dirty your car looks after being left outside for a couple of weeks? Well have fun washing your roof as often as you wash your car.